Prep the Meat: Take the lamb out of the refrigerator 1 hour before cooking to bring it to room temperature. Preheat your oven to 325°F (160°C).
Stud the Lamb: Using a sharp paring knife, make small, deep incisions (about 1 inch deep) all over the surface of the lamb. Insert one garlic sliver and one small tuft of rosemary into each incision.
The Herb Rub: Rub the entire surface of the roast with olive oil. Generously season with the sea salt and coarse black pepper, pressing the seasoning into the meat to create a savory crust.
The Roasting Pan: Place the lamb on a rack in a roasting pan. Pour the broth into the bottom of the pan (this keeps the meat moist and creates a base for your jus). If using vegetables, toss them in the pan around the meat.
Slow Roast: Roast for 20–25 minutes per pound for medium-rare (internal temp of 135°F/57°C). For fall-off-the-bone tenderness, you can cook slightly longer at a lower temperature.
The Essential Rest: Remove the lamb from the oven and transfer to a cutting board. Tent loosely with foil and let it rest for at least 20 minutes. This is the secret to a juicy, tender roast!
Serve: Shred the meat with a fork or slice against the grain. Spoon the glistening pan juices over the meat and serve while warm.